2011/5/20 innoway@mymelody.com:

I develop an embedded system on the Linux board with Freescale i.MX27 (ARM processor).   I succeed on sound, which is transferred using Synchronous Serial Interface (SSI). It,s fine and then I try to do test of inserting or pulling out a USB memory stick in the USB host connector while sounding.   I get the following error message from snd_pcm_lib_write1() of <linux src>/sound /core/pcm_lib.c after waiting for a while (about 10sec).       playback  write error (DMA or IRQ trouble?)   and then from snd_pcm_drain() of <linux src>/sound/core/pcm_native.c      playback drain error (DMA or IRQ trouble?)   (No sound during this period)

and then it is sounding again.

I want to prevent the sound from stopping even if something happens suddenly such as the USB memory stick is plugged in or out.

I try to fix the above programs, but I don't succeed.

Can someone give me the clue?   [13:21:38]:/proc# cat interrupts            CPU0  12:       3456         -  mxc_i2c  16:        141          -  CSPI_IRQ  18:        952          -  mxcintuart  26:    1051255     -  MXC Timer Tick  28:      29446        -  PCMCIA IRQ, ide0  50:         33           -  fec  54:        793          -  ehci_hcd:usb1  56:          1            -  arc_udc  61:          0            -  LCDC 117:          0           -  m66291_udc 147:          0           -  PMIC_IRQ 157:     337179     -  SMSC_LAN911x_ISR 176:          0           -  fec(MII)

[13:35:03]:/proc# cat dma dma channel  0: unused dma channel  1: unused dma channel  2: unused dma channel  3: unused dma channel  4: unused dma channel  5: unused dma channel  6: unused dma channel  7: unused dma channel  8: unused dma channel  9: unused dma channel 10: unused dma channel 11: unused dma channel 12: unused dma channel 13: unused dma channel 14: unused dma channel 15: unused   Thank you

Masanori Inoue

This error also occur in snd-hda-intel

echo 32768 > /proc/asound/Intel/pcm0p/sub0/prealloc

speaker-test which use maximum buffer size also have (DMA or IRQ error in system log

THis seem to be related to the schedule_timeout

tout = schedule_timeout(msecs_to_jiffies(10000));

I guess this is why PA server treat avail > 10 seconds is invalid